The present invention provides features to aid in the security or authentication of printed objects. We have found that a security feature is enhanced when it involves a multi-dimensional solution. To illustrate, we variously combine the principles of time, space and frequency when crafting such a multi-dimensional security feature. Multi-dimensional security features are readily applied to printed objects such as banknotes, checks, labels, product packaging, and identification documents.
For the purposes of this disclosure, identification documents are broadly defined and may include, e.g., credit cards, bank cards, phone cards, passports, driver's licenses, network access cards, employee badges, debit cards, security cards, visas, immigration documentation, national ID cards, citizenship cards, social security cards, security badges, certificates, identification cards or documents, voter registration cards, police ID cards, border crossing cards, legal instruments or documentation, security clearance badges and cards, gun permits, gift certificates or cards, labels or product packaging, membership cards or badges, etc., etc. Also, the terms “document,” “card,” and “documentation” are used interchangeably throughout this patent document. Identification documents are also sometimes referred to as “ID documents.”
Identification documents can include information such as a photographic image, a bar code (e.g., which may contain information specific to the person whose image appears in the photographic image, and/or information that is the same from ID document to ID document), variable personal information (e.g., such as an address, signature, and/or birth date, biometric information associated with the person whose image appears in the photographic image, e.g., a fingerprint), a magnetic stripe (which, for example, can be on the a side of the ID document that is opposite a side with a photographic image), and various designs (e.g., a security pattern like a printed pattern comprising a tightly printed pattern of finely divided printed and unprinted areas in close proximity to each other, such as a fine-line printed security pattern as is used in the printing of banknote paper, stock certificates, and the like). Of course, an identification document can include more or less of these types of features.
One exemplary ID document comprises a core layer (which can be pre-printed), such as a light-colored, opaque material, e.g., TESLIN, which is available from PPG Industries) or polyvinyl chloride (PVC) material. The core can be laminated with a transparent material, such as clear PVC to form a so-called “card blank”. Information, such as variable personal information (e.g., photographic information, address, name, document number, etc.), is printed on the card blank using a method such as Dye Diffusion Thermal Transfer (“D2T2”) printing (e.g., as described in commonly assigned U.S. Pat. No. 6,066,594, which is herein incorporated by reference), laser or inkjet printing, offset printing, etc. The information can, for example, comprise an indicium or indicia, such as the invariant or nonvarying information common to a large number of identification documents, for example the name and logo of the organization issuing the documents.
To protect the information that is printed, an additional layer of transparent overlaminate can be coupled to the card blank and printed information, as is known by those skilled in the art. Illustrative examples of usable materials for overlaminates include biaxially oriented polyester or other optically clear durable plastic film.
One type of identification document 100 is illustrated with reference to FIG. 1. The identification document 100 includes a machine-readable (e.g., digital watermark) security feature 102. The security feature 102 can be printed or otherwise provided on a substrate/core 120 or perhaps on a protective or decorative overlaminate 112 or 112′. The security feature 102 need not be provided on the “front” of the identification document 100 as illustrated, but can alternatively be provided on a backside of the identification document 100. The identification document 100 optionally includes a variety of other features like a photograph 104, ghost or faint image 106, signature 108, fixed information 110 (e.g., information which is generally the same from ID document to ID document), other machine-readable information (e.g., bar codes, 2D bar codes, optical memory) 114, variable information (e.g., information which generally varies from document to document, like bearer's name, address, document number) 116, etc. The document 100 may also include overprinting (e.g., DOB over image 106), microprinting (not shown), artwork, background patterns or tints, graphics, seals, etc. (all not shown). In some implementations security feature 102 overlaps or is embedded in at least one of the photograph, ghost image, artwork, background, graphics seals, etc.
Of course, there are many other physical structures/materials and other features that can be suitably interchanged for use with the identification documents described herein. The inventive techniques disclosed in this patent document will similarly benefit these other documents as well.
According to one aspect of the present invention, a printed document includes a machine-readable signal. The signal includes: a first set of print structures conveyed with first ink, and a second set of print structures convey with optical variable ink. The second set of print structure are provided to cooperate with the first set of print structures so that at a first observation angle the first set of print structures and the second set of print structures appear to provide uninterrupted print structures, and at a second observation angle the second set of print structures appear less observable to yield interrupted print structures. In some implementations the first set of print structures and the second set of print structures are lines or line segments.
Another aspect of the present invention is a printed document. The document includes a first set of elements provided on a surface of the printed document via first ink. The first ink has characteristics which require observation at a first angle and which are less observable at a second angle. The document further includes a second set of elements provided on the surface of the printed object via second ink. The second ink has a first emission decay rate and the second ink must be excited in a range of non-visible light in order to produce emissions. The first set of elements and the second set of elements cooperate to convey a machine-readable signal. The machine-readable signal is only observable at the first observation angle upon excitation in the range of non-visible light.
Still another aspect of the present invention is a printed document including a digital watermark printed thereon. The printed document has a property so that in response to an observation of the digital watermark, the digital watermark is altered to evidence the observation.
The foregoing and other features, aspects and advantages of the present invention will be even more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings.